Answer:
He still needs to fill 79.43% of the tank.
Explanation:
How much of the tank he filled?
1 3/4 gallons
As a decimal number, this is:
![1(3)/(4)=1+(3)/(4)=((4)/(1)\ast1+(4)/(4)\ast3)/(4)=(4+3)/(4)=(7)/(4)=1.75](https://img.qammunity.org/2023/formulas/mathematics/college/nry22fkbqnga4vizchxjrk3xxodr0jqp7o.png)
Conversion to liters:
1 gallon has 3.785 liters.
So, for 1.75 gallons, we have 1.75*3.785 = 6.62 liters.
The fish tank holds 32.176 liters.
So, he still needs to fill 32.176 - 6.62 = 25.556 liters.
What percentage of the tank does he still need to fill?
We divide what need to be filled by the total capacity, and multiply by 100. So
![(25.556)/(32.176)\ast100=0.7943\ast100=79.43](https://img.qammunity.org/2023/formulas/mathematics/college/uxqvm1q6e5eqqvc33daz98pfzekjsspvj7.png)
He still needs to fill 79.43% of the tank.